1. Field of the Invention
This invention relates generally to semiconductors, and more specifically, to switching devices for selectively coupling multiple bus masters to slave devices such as memories.
2. Description of the Related Art
A crossbar switch is typically used in a processing environment to improve the efficiency of a data processing system. A crossbar switch acts as a switching network that selectively interconnects multiple bus masters to multiple slaves via a dedicated, point-to-point interface. The crossbar switch reduces problems associated with bus utilization, bus arbitration and may provide higher memory bandwidth.
A crossbar switching network has a predetermined number of masters and slaves. Any master may communicate with any slave via the crossbar switch. Conventional crossbar switch implementations using multiple slave ports map each slave port into a mutually exclusive address range from a per master point of view. Different master ports may have different address maps for the slave ports. However, from an individual master's point of reference, all of the slave ports are mapped to mutually exclusive locations.
When using a multiple ported slave device, such as a memory controller, conventional switching circuits such as crossbar switches are inadequate. This is due to the mutually exclusive address decoding causing significant access queuing.
Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve the understanding of the embodiments of the present invention.